bandit666

I happened upon a set of c5 wheels cheap and am wondering if it is possible to safely mount them on a c4 with some kind of a spacer.I will need at least an inch spacer.1 1/4" would be perfect.I've thought about having spacers welded to the hub, but am concerned about warping or weakening the wheel due to the heat from welding.The c5 wheels are 10.5 inches wide with an 8 inch backspace.I have to get the backspace to 6.5 to no more than 7 inches.Any ideas and help will be appreciated.

1stVetteFinally

get a hudcentric spacer like this and you will be fine. I used a set like this to mount C6 rims on my '92 coupe that I circle track raced.

https://www.summitracing.com/parts/cal-75813/overview/

WVZR-1

How do you arrive at the idea that 1 1/4 would be ideal? I don't use back-spacing unless there's actually a tire/wheel mounted and it's confirmed that the back-spacing won't work, then try to make the tire/wheel fitment ideal for the car. I use calculations from the closest/widest OE configuration and work from there.

These are to be used front or rear on the car or X 4? You've an early C4 I believe.

I have thoughts on this and I'd think 1 1/4 is a stretch but I thought I'd ask first.

bandit666

I thought I could just get an answer to my question without having to explain my numbers, but here it is. The c5 wheels are 18"x 10 1/2" wide with an 8" backspace,58mm offset.The wheels I have on it now are 1996- 17"x 9 1/2 wide with a 6 3/4 backspace,50mm offset , 8mm difference=aprox.3/8".These wheels clear by about 2" with 315x35-17 tires.Note: I'm only concerned with this on the rear.Front wheels are narrower, so no issue there.So, 8 minus 6 3/4 = 1 1/4" plus the extra 3/8" offset makes it 1 5/8" difference(or closer to the inside of wheel well to rubbing).I already have about 2" clearance with the current wheels and tires, but will be going to a bigger tire with the 18s,so
I want to stay at at least 1 1/2"- 2" clearance.So, to keep my clearance at 2" the math says I need a 1 5/8" spacer.A 1 1/4 spacer would give me 1 7/8" clearance,a 1" spacer would give me 1 5/8" clearance.I prefer the 1 1/4" spacer due to the bigger tires and any possible tire flex but the 1" spacer would probably work.Also I dismounted one of my 17" tires and measured my clearance with just the wheel mounted on the hub,(with jack under shock mount) then put a 1 1/4" worth of washers on the lug bolts with the c5 wheel and measured it.Real close to the same clearance of the 17" wheel.Wheew,there ya go.This was actually fun splaining it.

bob arrowsmith

i have c5 rims and stock width tires on my 96 with the above mentioned spacer on the rear, fits perfect and the tire just barely sticks out past the lip which i think looks good, if you use a 1.4 spacer with 315 tires it will stick out further.. only you will know if you like that look..do not weld, you will be asking for trouble.. when i put the spacers on the front it through my geometry off and felt unstable so i left them off of the front. too me it was not worth the extra effort and money to make them workl.

bandit666

I like the look of them sticking out a little.Where did you get the spacer from and which one? part number would be a big help.thanks

WVZR-1

This is for an '87 or earlier car correct? That is what I thought you have. Have you put later '88+ suspension in it by any chance?


For starters this is likely 'wrong'. A 9.5 @ 38 is 6 3/4



Now if I were doing this for the rear I'd do all of my comparisons using an 11" @ 36 which most mention fits an early car with no issues. No problem comparing to a 9.5@38 either.

I'd think a 19mm or 3/4 would make the 10.5 @58 an 'ideal' fit for the rear.

You can't use numbers mentioned by anyone that mentions a car '88 or newer!!!

****Play with #'s 19 - 24mm or 3/4 - 1". Those are generally the least expensive and on the shelf for quick ships. To 'tailor' the fitment I'd think might require something in the 'middle' but they get expensive and won't quick ship from anyone.

bandit666

car is an 87 with an 86 d44 rear.I believe an 86 d36-44 is the same as an 86 d36-44.I ask about spacer part number because I wonder about hub center bore fitment.Mine is 70.3 mm or 2.768 in.

bandit666

meant to say an 87 I believe is the same as an 86

WVZR-1

70.3 is correct for hub diameter for center-bore.

Did the numbers I mention make better sense after you redid some math? A 10 1/2 on the rear of any C4 can be a very pleasant fit and maybe be ideal!!

What are you going to use for your 1st attempt?

bandit666

My concern there would be that the center bore on that spacer is 74mm. Hub size is 70.3mm. With the slop there and slop around lug holes it seems to me that it would be impossible to get centered perfectly and keep from wobling.Although once bolted on the lug nuts would probably center the wheel on the spacer, but the spacer still is sloppy on the hub.

bandit666

Never mind,after a closer look I see that the spacer bolts to the hub, which would center it on the hub.My bad

bandit666

I didn't re do the math with your numbers as I don't want to compare them to a 11' whatever offset-backspace wheel that I don't have.I know what I need.1stvettefinally had a link to a spacer from summit racing on there that I'm sure will work.Thanks.

bandit666

I didn't re do the math with your numbers as I don't want to compare them to a 11' whatever offset-backspace wheel that I don't have.I know what I need.1stvettefinally had a link to a spacer from summit racing on there that I'm sure will work.Thanks.

bandit666

Thanks,I just did all the measuring and that spacer will be perfect.

1stVetteFinally

which is exactly why I recommended that exact spacer